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Background: Patients with skin lesions suspicious for skin cancer or atypical melanocytic nevi of uncertain malignant potential often present to dermatologists, who may have variable dermoscopy triage clinical experience., Objective: To evaluate the clinical utility of a digital dermoscopy image-based artificial intelligence algorithm (DDI-AI device) on the diagnosis and management of skin cancers by dermatologists., Methods: Thirty-six United States board-certified dermatologists evaluated 50 clinical images and 50 digital dermoscopy images of the same skin lesions (25 malignant and 25 benign), first without and then with knowledge of the DDI-AI device output. Participants indicated whether they thought the lesion was likely benign (unremarkable) or malignant (suspicious)., Results: The management sensitivity of dermatologists using the DDI-AI device was 91.1%, compared to 84.3% with DDI, and 70.0% with clinical images. The management specificity was 71.0%, compared to 68.4% and 64.9%, respectively. The diagnostic sensitivity of dermatologists using the DDI-AI device was 86.1%, compared to 78.8% with DDI, and 63.4% with clinical images. Diagnostic specificity using the DDI-AI device increased to 80.7%, compared to 75.9% and 73.6%, respectively., Conclusion: The use of the DDI-AI device may quickly, safely, and effectively improve dermoscopy performance, skin cancer diagnosis, and management when used by dermatologists, independent of training and experience.

Competing Interests: None disclosed.

Competing Interests: Dr Correa-Selm is a consultant for Accutec and a consultant and researcher for Novartis Pharmaceutical, also serves on the Advisory Board for the Jacinto Convit World Organization and the Dermatology Advisory for Melanoma Research Foundation. Dr Grichnik is a consultant for Galileo Group and Canfield Scientific; serves on the Skin Advisory Board for Regeneron and the Dermatology Advisory for Melanoma Research Foundation; and receives clinical trial support from Novartis, Eli Lilly, Dermira, Elorac, Boehringer, and Amgen. Author Milani, Author Hanlon, and Dr Chen have no conflicts of interest to declare.

Significance: Dermoscopes incorporate light, polarizers, and optical magnification into a handheld tool that is commonly used by dermatologists to evaluate skin findings. Diagnostic accuracy is improved when dermoscopes are used, and some major artificial intelligence (AI) projects have been accomplished using dermocopic images. Color rendering consistency and fidelity are crucial for clinical diagnostics, AI, and image processing applications., Aim: With many devices available on the market, our objective was to measure the emission spectra of various dermoscopes, compare them with other light sources, and illustrate variations in reflected colors from images of a reference sample., Approach: A spectrometer measured the spectral power distribution (SPD) produced by four dermoscope models and three alternate light sources, illustrating differences in the emission spectra. Most dermoscopes use light-emitting diodes (LEDs), which are inconsistent when compared with one another. An LED was compared with halogen, xenon-arc, and daylight sources. Images of a micro ColorChecker were acquired from several sources, and three specific colors were selected to compare in CIELAB color space. Color consistency and color fidelity measured by color rendering index (CRI) and TM-30-18 graphical vectors show variation in saturation and chroma fidelity., Results: A marked degree of variation was observed in both the emission and reflected light coming from different dermoscopes and compared with other sources. The same chromophores appeared differently depending on the light source used., Conclusions: A lack of uniform illumination resulted in inconsistent image color and likely impacted metamerism and visibility of skin chromophores in real-world settings. Artificial light in skin examinations, especially LEDs, may present challenges for the visual separation of specific colors. Attention to LEDs SPD may be important, especially as the field increases dependency on machine/computer vision., (© 2022 The Authors.)

Competing Interests: Dr Grichnik serves as a consultant for Galileo Group, Canfield Scientific and has previously received equipment and meeting support from Caliber Imaging and Diagnostics. Dr Correa-Selm served as speaker of Accutec Blades and was a consultant for Castle Biosciences. Authors Blumstein and Hanlon and Drs Chen and Elgart have no conflicts of interest to declare.

Identification and removal of melanoma early in its development remains the most effective treatment. However, identification of early melanoma remains challenging and may result in unnecessary morbidity due to the excess excision of benign melanocytic nevi. Herein, we present a conceptual model of benign and malignant melanocytic growths. The potential differences in the location of the cell of origin as well as considerations for neoplasm progression are also reviewed. Several of the clinical tools currently available, the integration of information from those different sources, and approaches to set an optimum biopsy threshold are discussed. While early detection remains a challenge, significant progress has been made. Insight into melanoma growth processes and appropriate use of available tools can result in the detection of thinner melanomas while also decreasing overall biopsy rates., Competing Interests: Financial & competing interests disclosure JM Grichnik has served as a consultant for Amgen, Caliber Imaging & Diagnostics, Inc., Castle Biosciences, and Novartis and is a major shareholder in DigitalDerm, Inc. This manuscript was supported by the Anna Fund Melanoma Program at Sylvester Comprehensive Cancer Center, and the Frankel Family Division of Melanocytic Tumors, Department of Dermatology and Cutaneous Surgery, University of Miami and benefactors especially W Rubin and his family and friends. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.

Melanomas demonstrate chromosomal instability (CIN). In fact, CIN can be used to differentiate melanoma from benign nevi. The exact molecular mechanisms that drive CIN in melanoma have yet to be fully elucidated. Cancer/testis antigens are a unique group of germ cell proteins that are found to be primarily expressed in melanoma as compared to benign nevi. The abnormal expression of these germ cell proteins, normally expected only in the testis and ovaries, in somatic cells may lead to interference with normal cellular pathways. Germ cell proteins that may be particularly critical in CIN are meiosis proteins. Here, we review pathways unique to meiosis with a focus on how the aberrant expression of meiosis proteins in normal mitotic cells "meiomitosis" could impact chromosomal instability in melanoma and other cancers.

Early diagnosis gives melanoma patients the best chance for long term survival. However discrimination of an early melanoma from an unusual/atypical benign nevus can represent a significant challenge. There are no current pathological markers to definitively define malignant potential in these indeterminate lesions. Thus, there is a need for improved diagnostic tools. Chromosomal instability (CIN) is a hallmark of cancer and is markedly prevalent in melanoma. Advances in genomics have opened the door for the development of molecular tools to better segregate benign and malignant lesions. This paper focuses on CIN in melanoma and the role of current diagnostic approaches.

Germ cell protein expression in melanoma has been shown to correlate with malignancy, severity of disease and to serve as an immunologic target for therapy. However, very little is known about the role that germ cell proteins play in cancer development. Unique germ cell pathways include those involved in immortalization, genetic evolution, and energy metabolism. There is an ever increasing recognition that within tumors there is a subpopulation of cells with stem-cell-like characteristics that play a role in driving tumorgenesis. Stem cell and germ cell biology is intertwined. Given the enormous potential and known expression of germ cell proteins in melanoma, it is possible that they represent a largely untapped resource that may play a fundamental role in tumor development and progression. The purpose of this paper is to provide an update on the current value of germ cell protein expression in melanoma diagnosis, prognosis, and therapy, as well as to review critical germ cell pathways and discuss the potential roles these pathways may play in malignant transformation.

Embryonic stem cells, mesenchymal stem cells and induced pluripotent stem cells expanded in vitro exhibit genomic instability. Commonly reported abnormalities include aneuploidy, deletions and duplications (including regions also amplified in cancer). Genomic instability confers an increased risk of malignant transformation that may impact the safety of cultured stem cell transplantation. Possible mechanisms responsible for this genomic instability include DNA repair mechanism abnormalities, telomere crisis, mitotic spindle abnormalities and inappropriate induction of meiotic pathways. Prior to widespread use of these cells in regenerative medicine, it will be critical to gain an understanding of the mechanisms responsible for genomic instability to develop strategies to prevent the accrual of chromosomal defects during expansion in vitro.

In previous research, a watershed-based algorithm was shown to be useful for automatic lesion segmentation in dermoscopy images, and was tested on a set of 100 benign and malignant melanoma images with the average of three sets of dermatologist-drawn borders used as the ground truth, resulting in an overall error of 15.98%. In this study, to reduce the border detection errors, a neural network classifier was utilized to improve the first-pass watershed segmentation; a novel "edge object value (EOV) threshold" method was used to remove large light blobs near the lesion boundary; and a noise removal procedure was applied to reduce the peninsula-shaped false-positive areas. As a result, an overall error of 11.09% was achieved., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

It is generally accepted that cutaneous nevogenesis is a localized event that occurs exclusively in the dermis and/or epidermis. However, the discovery of nevocytes circulating in the peripheral blood suggests that other, more systemic, benign metastatic processes could also be involved. The theoretical role of lymphatic and hematogenous dissemination of loosely adherent, immature nevus progenitor cells in the development of nodal nevi and eruptive melanocytic nevi will be reviewed.

Melanomas and nevi share many of the same growth-promoting mutations. However, melanomas grow relentlessly while benign nevi eventually undergo growth arrest and stabilize. The difference in their long-term growth potential may be attributed to activation of cellular senescence pathways. The primary mediator of senescence in nevi appears to be p16. Redundant, secondary senescence systems are also present and include the p14-p53-p21 pathway, the IGFBP7 pathway, the FBXO31 pathway, and the PI3K mediated stress induced endoplasmic reticulum unfolded protein response. It is evident that these senescence pathways result in an irreversible arrest in most instances; however, they can clearly be overcome in melanoma. Circumvention of these pathways is most frequently associated with gene deletion or transcriptional repression. Reactivation of senescence mechanisms could serve to inhibit melanoma tumor progression.

Despite recent advances, the biology underlying nevogenesis remains unclear. Activating mutations in NRAS, HRAS, BRAF, and GNAQ have been identified in benign nevi. Their presence roughly correlates with congenital, Spitz, acquired, and blue nevi, respectively. These mutations are likely to play a critical role in driving nevogenesis. While each mutation is able to activate the MAP kinase pathway, they also interact with a host of different proteins in other pathways. The different melanocytic developmental pathways activated by each mutation cause the cells to migrate, proliferate, and differentiate to different extents within the skin. This causes each mutation to give rise to a characteristic growth pattern. The exact location and differentiation state of the cell of origin for benign moles remains to be discovered. Further research is necessary to fully understand nevus development given that most of the same developmental pathways are also present in melanoma.

It is now well established that a subpopulation of tumor stem cells (TSCs) are present within cancer tissues. This suggests that tumors evolve from stem cells; however, the exact cell of tumor origin, the potential role of dedifferentiation, and the role of plasticity in tumor development are largely unknown. A model cancer for the study of the oncologic process is melanoma. The developmental biology of melanocytes is relatively well understood, the cells pigment as they differentiate making them easy to identify, and benign and malignant tumors develop on the skin surface allowing direct observation of growth features, early detection, and removal. This ready access to early-stage tumors will facilitate study of the early oncologic processes and the role of tissue stem cells. Melanomas, like other cancers, include a subpopulation of TSCs. These TSCs have access to embryologic developmental programs, including the capacity to differentiate along multiple cell lineages. For example, melanomas can activate germ-cell pathways with major implications for TSC self-renewal through the activation of telomerase and genomic instability through the collision of meiotic and mitotic pathways (meiomitosis). The TSC model is still evolving, but the existence of TSCs has significant ramifications for tumor development, diagnosis, prognosis, and treatment of melanoma and other cancers.

Wang et al. point to the existance of a common progenitor tumor stem cell that gives rise to genomically unstable progeny in malignant melanoma. Although it is not known what creates this genomic instability, given the presence of testis antigens in melanoma, it is tempting to speculate that it is caused by a collision of meiotic and mitotic pathways.

As described in this issue, Alexeev and Yoon introduced a Kit-activating mutation into melanocytes. Although mitogenic in mast cells, this mutation was motogenic in melanocytes. Further, melanocytes had a reduced proliferative rate and were less differentiated. The disparate response may be due to differences in the cellular milieu of melanocytes and may have implications for normal melanocytic integration into the epidermis, nevogenesis, and melanoma.

Stem cells play a critical role in normal tissue maintenance, and mutations in these stem cells may give rise to cancer. We hypothesize that melanoma develops from a mutated stem cell and therefore residual stem cell characteristics should be able to be identified in melanoma cell lines. We studied three metastatic melanoma cell lines that exhibited multiple morphologic forms in culture and demonstrated the capacity to pigment. We used the ability to efflux Hoechst 33342 dye, a technique known to enrich for stem cells in many tissues, to segregate cell populations. The cells with the greatest ability to efflux the dye were (1) small in size, (2) had the capacity to give rise to larger cell forms, and (3) had the greatest ability to expand in culture. The small cells were found to have a decreased proliferative rate and were less melanized. Large dendritic cells that appeared to be nonproliferative were identified in cultures. Treatment with cytosine beta-D-arabinofuranoside hydrochloride (Ara-C) expanded the large cell population but the residual proliferative capacity, both in vitro and in vivo, remained concentrated in the smaller cell fraction. Antigenic staining patterns were variable and heterogeneous. Nestin (a neural stem cell marker) and gp100 (premelanosomal marker) favored the smaller cell population, while nerve growth factor receptor often labeled larger cells. Morphologic and antigenic heterogeneity remained intact after clonal purification. These findings are consistent with the behavior expected for a tumor based on stem cell biology; this finding has diagnostic and therapeutic implications for melanocytic neoplasias.

Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15%l-ascorbic acid and 1%alpha-tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. Inhibition of apoptosis was associated with reduced induction of caspase-3 and caspase-7. This antioxidant formulation efficiently reduced thymine dimer formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.

Purpose: The purpose of this study was to evaluate the feasibility of incorporating a novel wound angiogenesis assay into a Phase I study of BMS-275291, a broad-spectrum matrix metalloproteinase inhibitor, and to determine whether the wound angiogenesis assay was able to detect the inhibition of angiogenesis in patients treated with BMS-275291., Experimental Design: Before treatment began, a 4-mm skin biopsy was performed. The wound was imaged for 14 days. Treatment was started on day 0, and a separate 4-mm biopsy was performed 14 days later. The second wound was also imaged for 14 days. Wound angiogenesis was scored by two independent observers who were blinded to treatment status., Results: The median times in days (95% confidence interval) to reach the target average vascular score (AVS) of 1.5 and 2.0 based on the data of Observer 1 were 3.7 (2.2-6.9) and 8.0 (5.0-10.0) pretreatment whereas on-treatment the values were 4.9 (3.7-8.0) and 9.3 (7.0-11.5), respectively. The delay in the median time to reach an AVS of 1.5 was 1.2 days or a 32% reduction when comparing pretreatment with on-treatment (P = 0.06). For the target AVS of 2.0 the delay in the median time pretreatment versus on-treatment was 1.3 days or a 16% reduction (P = 0.04)., Conclusions: The wound angiogenesis assay used in this study was practical, well tolerated, and reproducible. Delays in wound angiogenesis because of BMS-275291 were detectable with this assay. This technique warrants additional investigation in clinical trials of other antiangiogenic agents.

During development, the interaction of stem cell factor (SCF) with its receptor, KIT, is critical for the survival of melanocytes. Limited in vivo human studies have suggested a possible activating role of SCF on adult human melanocytes. In order to study the impact of this pathway on normal melanocyte homeostasis, human skin xenografts were treated with serial injections of recombinant human SCF or a KIT-inhibitory antibody (K44.2). On histologic evaluation, SCF injection increased, whereas KIT inhibition decreased the number, size, and dendricity of melanocytes. Immunohistochemical expression of melanocyte differentiation antigens, including tyrosinase-related-protein-1 and gp100/pmel17, was markedly increased by treatment with SCF, and decreased by K44.2 treatment. The number of Ki67-positive melanocytes was increased in the SCF-treated tissue, suggesting a direct proliferative effect of SCF; conversely, treatment with K44.2 resulted in melanocyte loss, which did not appear reversible with prolonged treatment. These findings demonstrate that the SCF/KIT pathway remains critical in adult human skin, and that pharmacologic modulation of this single pathway can control cutaneous melanocyte homeostasis.

Human skin is believed to harbor a reservoir population of precursor melanocytes. It has been difficult to identify these putative cells experimentally, because they lack phenotypic features that define mature melanocytes. We have evaluated expression of the KIT tyrosine kinase receptor, which is critical for melanocyte development, as a possible marker of these cells. Sections of human skin were evaluated with single- and double-immunolabeling techniques. KIT-reactive dendritic cells were identified in the basal layer of the epithelia and were most numerous in the follicular infundibula and the rete ridges. These cells were located on the epithelial side of the basement membrane and lacked expression of cytokeratin and mast cell tryptase. The location of the KIT-reactive cells was distinctly different from that of Langerhans cells (identified with anti-CD1a) or Merkel cells (identified with CAM 5.2). Within the epidermis and upper follicular infundibulum the majority of the KIT-reactive dendritic cells also coexpressed TRP-1, a marker present in differentiated melanocytes. In the deeper follicular regions, the coexpression of TRP-1 in the KIT-reactive cells was absent. Throughout the epidermis and follicle, however, the KIT-reactive cells coexpressed BCL-2, a marker known to be increased in melanocytes. Thus, KIT expression reveals a population of intraepithelial cells that have immunophenotypic characteristics of mature melanocytes within the upper epithelial regions, but lack the differentiated melanocytic phenotype within the deeper follicular regions. We propose that these KIT(+), BCL-2(+), and TRP-1(-) cells constitute a precursor melanocyte reservoir of human skin.

An assay system for transcriptional profile analysis of cultured eukaryotic cells has been developed to simultaneously handle multiple samples in a rapid, sensitive, and internally controlled manner. The methodology incorporates a microtiter plate assay system, a rapid cell-harvest enzyme-assay technique, and the bacterial reporter genes beta-glucuronidase and beta-galactosidase. We demonstrate, using beta-actin and SV40 (late) transcription promoting sequences, that this technically refined microtiter-triton-lysate (MTL) assay methodology can readily differentiate between the transcriptional states of human melanocytes before and after pharmacologic stimulation and malignantly transformed versus normal cell environments. Differences in the transcriptional environments are revealed by the relative expression of transcription element probes. The transcriptional activity ratio of the beta-actin compared to the SV40 late transcription promoting sequences was approximately 1:2 in primary cultured melanocytes, 2:1 in 12-0-tetradecanoyl phorbol-13-acetate (TPA)-treated melanocytes and 1:4 in the Tang melanoma cell line. Because this MTL assay methodology can accommodate a panel of transcription element probes, we anticipate that the resultant transcriptional profiles will prove useful in deciphering the diverse transcriptional changes that occur within normally regulated and malignantly transformed cells.

We have previously observed that DNA sequences within the 5'-flanking region of the chicken skeletal alpha-actin gene harbor a cis-acting regulatory element that influences cell type and developmental stage-specific expression (J. M. Grichnik, D. J. Bergsma, and R. J. Schwartz, Nucleic Acids Res 14:1683-1701, 1986). In this report we have constructed unidirectional 5'-deletion and region-specific deletion-insertion mutations of the chicken skeletal alpha-actin upstream region and inserted these into the chloramphenicol acetyltransferase expression vector pSV0CAT. These constructions were used to locate DNA sequences that are required for developmental modulation of expression when transfected into differentiating myoblasts. With this assay we have delimited the 5' boundary of a cis-acting regulatory element to ca. 200 base pairs upstream of the mRNA cap site. In addition, we have preliminarily identified DNA sequences that may be important subcomponents within this element. A second major focus of this study was to identify those DNA signals within the regulatory element that control transcription. Toward this end, the expression phenotypes of progressive 5'-deletion and deletion-insertion mutants of the 5'-flanking region of the chicken skeletal alpha-actin gene were assayed in microinjected Xenopus laevis oocytes. These experiments defined a cis-acting transcriptional control region having a 5' border 107 base pairs preceding the alpha-actin RNA cap site. Proximal and distal functionally important regions of DNA were identified within this element. These DNA signals included within their DNA sequences the "CCAAT" and "TATA" box homologies.

alpha-skeletal actin message levels have been shown to be tightly regulated in chicken primary myoblast cultures. To test for gene elements required for muscle cell specific expression, DNA sequences containing the 5'-flanking regions of the chicken alpha-skeletal actin, beta-cytoplasmic actin, and the histone H2b genes were linked to the coding sequences of the chloramphenicol acetyltransferase gene and transfected into myogenic and non-myogenic cells. In contrast to beta-actin CAT hybrids, the alpha-skeletal actin CAT constructions displayed restricted CAT expression in transfected non-myogenic cells. We showed that a 411 nucleotide fragment flanking the 5' end of of the alpha-skeletal actin gene was responsible for a 9-15 fold increase in CAT enzymatic activity during myoblast fusion, versus only a transient 2 fold rise for the beta-actin and histone flanking sequences. These results indicate that DNA sequences within 411 bp of the 5' terminus of the alpha-skeletal actin gene influenced its cell type and stage specific expression.

The chicken skeletal alpha-actin gene promoter region (-202 to -12) provides myogenic transcriptional specificity. This promoter contains partial dyad symmetry about an axis at nucleotide -108 and in transfection experiments is capable of directing transcription in a bidirectional manner. At least three different transcription initiation start sites, oriented toward upstream sequences, were mapped 25 to 30 base pairs from TATA-like regions. The opposing transcriptional activity was potentiated upon the deletion of sequences proximal to the alpha-actin transcription start site. Thus, sequences which serve to position RNA polymerase for alpha-actin transcription may allow, in their absence, the selection of alternative and reverse-oriented start sites. Nuclear runoff transcription assays of embryonic muscle indicated that divergent transcription may occur in vivo but with rapid turnover of nuclear transcripts. Divergent transcriptional activity enabled us to define the 3' regulatory boundary of the skeletal alpha-actin promoter which retains a high level of myogenic transcriptional activity. The 3' regulatory border was detected when serial 3' deletions bisected the element (-91 CCAAA TATGG -82) which reduced transcriptional activity by 80%. Previously we showed that disruption of its upstream counterpart (-127 CCAAAGAAGG -136) resulted in about a 90% decrease in activity. These element pairs, which we describe as CCAAT box-associated repeats, are conserved in all sequenced vertebrate sarcomeric actin genes and may act in a cooperative manner to facilitate transcription in myogenic cells.